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What should I check if my 2021 Toyota Highlander won't start? - Toyota Highlander
Home/Cars/Toyota/Highlander/Fourth Generation (2020-present)/What should I check if my 2021 Toyota Highlander won't start?

What should I check if my 2021 Toyota Highlander won't start?

Toyota Highlander Fourth Generation (2020-present)

Error Codes
medium
Difficulty
medium
Severity
Navigation
ProblemSymptomsDiagnosisSolution
ProblemSymptomsDiagnosisSolution
5 min read
801 words

Problem Statement

Learn how to diagnose and troubleshoot starting issues with your 2021 Toyota Highlander, including symptoms, diagnostic steps, and repair instructions.

Affected Component
starting system

Symptoms

  • •No response when turning the key or pressing the start button.
  • •Engine cranks but does not start.
  • •Dashboard lights flicker or dim.
  • •Clicking sound when attempting to start.
  • •No lights or sounds at all when trying to start.

Diagnostic Steps

  1. 1
  2. 2
  3. 3
  4. 4
  5. 5

Solution

💡 Expert Tip

For complex repairs like this, consider taking photos at each step. This helps if you need to reverse a step or consult with a mechanic. Also, keep all removed parts organized - you may need to reference them during reassembly.

Verification

After completing the repair, verify that the issue has been resolved:

  • ✓Test the affected component to ensure it functions correctly
  • ✓Check for any error codes or warning lights
  • ✓Monitor the vehicle for a few days to ensure the issue does not recur

Prevention Tips

To prevent this issue from occurring again:

  • •Follow the manufacturer's recommended maintenance schedule
  • •Address warning signs early before they develop into major issues
  • •Use quality parts and fluids recommended for your vehicle
  • •Keep detailed records of all repairs and maintenance

Tools & Equipment Required

  • •Multimeter
  • •Battery tester
  • •Jumper cables
  • •Fuse puller
  • •Needle nose pliers
  • •Screwdriver or socket set
  • •Test light
  • •Fuel pressure gauge
  • •Basic hand tools
  • •Spark tester

Additional Information

Affected Component
starting system
Difficulty
medium
Severity
medium
Tools Required
10 items

Related Faults

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Back to Generation

If your 2021 Toyota Highlander won't start, there are several potential causes that you can diagnose before seeking professional help. Below are the symptoms, diagnostic steps, tools required, and repair instructions to troubleshoot the issue effectively.

Step 1: Check the Battery

  • Symptoms: If the lights flicker or are dim, or if there's a clicking sound.
  • Tools Required: Multimeter or a battery tester, jumper cables.

  1. Inspect Battery Condition:

    • Look for corrosion on the battery terminals. Clean any corrosion with a battery terminal cleaner or a mixture of baking soda and water.

  2. Test Battery Voltage:

    • Using a multimeter, set it to DC voltage and check the battery voltage. A healthy battery should read around 12.6 volts or more.
    • If the voltage is below 12.4 volts, consider charging or replacing the battery.

  3. Jump Start the Vehicle:

    • If the battery seems weak, connect jumper cables to a working vehicle and attempt to start your Highlander. If it starts, you may need to replace the battery or check the charging system.

Step 2: Inspect the Fuses

  • Symptoms: If the vehicle shows no signs of life.
  • Tools Required: Fuse puller or needle nose pliers, multimeter (optional).

  1. Locate the Fuse Box:

    • The fuse box is typically located under the dashboard on the driver's side and/or in the engine compartment.

  2. Check Relevant Fuses:

    • Inspect fuses related to the ignition system, starter, and ECM (Engine Control Module).
    • Replace any blown fuses and reattempt to start the vehicle.

Step 3: Starter System Check

  • Symptoms: If you hear a clicking sound but the engine does not crank.
  • Tools Required: Multimeter, screwdriver or socket set, test light.

  1. Test Starter Relay:

    • Locate the starter relay in the fuse box. Use a multimeter or test light to check if the relay is functioning properly.

  2. Check Starter Voltage:

    • Ensure that the starter is receiving the correct voltage when the key is turned to the start position (approximately 12V).

  3. Inspect Starter Connections:

    • Check the wiring and connections to the starter for signs of corrosion or damage. Tighten any loose connections.

  4. Bench Test Starter:

    • If necessary, remove the starter and perform a bench test to check if it operates properly.

Step 4: Fuel System Check

  • Symptoms: Engine cranks but does not start.
  • Tools Required: Fuel pressure gauge, multimeter, basic hand tools.

  1. Check Fuel Pump Operation:

    • Turn the ignition to the "ON" position (without starting) and listen for the fuel pump sound.

  2. Test Fuel Pressure:

    • Connect a fuel pressure gauge to the fuel rail and check for proper fuel pressure according to specifications (usually around 50-60 PSI).

  3. Inspect Fuel Filter:

    • If pressure is low, check the fuel filter for clogs and replace it if necessary.

Step 5: Ignition System Check

  • Symptoms: Engine cranks but does not start.
  • Tools Required: Spark tester, multimeter, basic hand tools.

  1. Check for Spark:

    • Remove a spark plug, connect it to a spark tester, and crank the engine. You should see a strong blue spark.

  2. Inspect Ignition Components:

    • Check the ignition coils and wiring for defects.
    • Replace any faulty ignition components.
Repair Instructions

Battery Replacement

  1. Disconnect the negative terminal first, followed by the positive terminal.
  2. Remove the old battery and install the new one.
  3. Connect the positive terminal first, followed by the negative terminal.

Fuse Replacement

  1. Remove the blown fuse using a fuse puller.
  2. Insert a new fuse of the same amperage.
  3. Test the system after replacing.

Starter Replacement

  1. Disconnect the battery.
  2. Remove the starter bolts and electrical connections.
  3. Install the new starter, reconnect electrical connections, and secure it in place.
  4. Reconnect the battery and test.

Fuel Pump Replacement

  1. Relieve fuel pressure from the system.
  2. Remove the fuel pump access panel (if applicable) or drop the fuel tank.
  3. Replace the fuel pump and reassemble the system.
  4. Reconnect the battery and test.

Ignition Component Replacement

  1. Remove the spark plug or ignition coil.
  2. Install the new component and reconnect wiring.
  3. Test the system.
Conclusion

By following these diagnostic steps and repair instructions, you should be able to identify and potentially resolve the issue preventing your 2021 Toyota Highlander from starting. If the problem persists after these checks, it may be necessary to consult a professional mechanic for further diagnosis.